chain_getHeader

Description

Returns the header for a given block hash. When params are omitted, it returns the header for the most recent block known to the node (best or finalized, depending on implementation). Use this to track block numbers, parent hashes, and state/extrinsics roots.

Parameters

Parameter	Type	Required	Description
blockHash	string	No	Hex-encoded block hash. If omitted, the latest block header is returned

Returns

Field	Type	Description
parentHash	string	Hash of the parent block
number	string	Block number encoded as hex
stateRoot	string	State trie merkle root
extrinsicsRoot	string	Extrinsics merkle root
digest	object	Digest logs (
preRuntime, consensus, seal, etc.)

Request Example

{
  "jsonrpc": "2.0",
  "method": "chain_getHeader",
  "params": [
    "0xd4b3a0e3b88b7c25215926bbf7c733f5c31e69c0c8c4b4a86d6ec3f3f086e95d"
  ],
  "id": 1
}

Response Example

{
  "jsonrpc": "2.0",
  "result": {
    "parentHash": "0x65b246e9b69a61f842104a15307ae906013c56a8bb6c942555b1a71424b4bab3",
    "number": "0x9055f2",
    "stateRoot": "0x220ea5bd35df99176268d8cbcee287a8a81a2e8addfa764661f71af591db0329",
    "extrinsicsRoot": "0x388e5e2bb951b1dfac3f6a3f0c1d5de1ace6e413008efe48f1a54228dcd049db",
    "digest": {
      "logs": [
        "0x0661757261208a2c7a1100000000",
        "0x0452505352903006d1651014effe612aeb9e2bed207fca849e69a1d4594bdab580afc68677458a62ad06"
      ]
    }
  },
  "id": 1
}

Headers are captured from block #9,053,714 on 2025-10-03 07:42:18 UTC.

Code Examples

cURL

curl https://api-bifrost-polkadot.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "chain_getHeader",
    "params": [],
    "id": 1
  }'

JavaScript

const response = await fetch('https://api-bifrost-polkadot.n.dwellir.com/YOUR_API_KEY', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    jsonrpc: '2.0',
    method: 'chain_getHeader',
    params: ['0xd4b3a0e3b88b7c25215926bbf7c733f5c31e69c0c8c4b4a86d6ec3f3f086e95d'],
    id: 1
  })
});

const { result } = await response.json();
console.log(parseInt(result.number, 16));

Rust (subxt)

use subxt::{config::substrate::SubstrateConfig, OnlineClient};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let api = OnlineClient::<SubstrateConfig>::from_url(
        "wss://api-bifrost-polkadot.n.dwellir.com/YOUR_API_KEY"
    ).await?;

    let hash = "0xd4b3a0e3b88b7c25215926bbf7c733f5c31e69c0c8c4b4a86d6ec3f3f086e95d".parse()?;
    let header = api.rpc().header(Some(hash)).await?.expect("header");
    println!("Block #{}", header.number);
    println!("State root {}", header.state_root);
    Ok(())
}

Usage Notes

• When replaying blocks, pair chain_getHeader with chain_getBlock to fetch extrinsics and events.
• Use chain_getHeader + chain_getFinalizedHead to confirm finality before crediting cross-chain transfers.